Abrasive cutting-off wheels having metal coated sides

ABSTRACT

Cutting-off wheels are provided having an abrasive matrix including a plurality of abrasive grains and a resinous bonding agent. The cutting-off wheels have affixed to both sides thereof a metal-bearing plastic coating. This metallized plastic coating acts as a reflective barrier to heat transmitted by radiation during the cutting process.

United States Patent Rue et a1.

2 51 3,686,800 51 Aug. 29, 1972 [54] ABRASIVE CUTTING-OFF WHEELS HAVING METAL COATED SIDES [72] Inventors: Charles V. Rue, Clinton Township;

John F. Busch, Tiffin, both of Ohio [73] Assignee: International Telephone and Telegraph, Corporation, New York, NY. 7

[22] Filed: Dec. 22, 1969 [21] Appl. No.: 887,000

[52] US. Cl. ..51/206 R, 51/297 [51] Int. Cl. ..B24d 5/04 [58] Field of Search ..51/206 R, 206 NF, 207, 297' [56] References Cited UNITED STATES PATENTS 1,600,064 9/1926 1 Perks ..51/206 X ing the cutting process.

Primary Examiner-Lester M. Swingle.

Attorney-C. Cornell Remsen, .lr., Walter J. Baum, Percy P. Lantzy, J. Warren Whitesel, Delbert P. Warner and James B. Raden [57] ABSTRACT Cutting-off wheels are provided having an abrasive matrix including a'plurality of abrasive grains and a resinous bonding agent. The cutting-01f wheels have affixed: to both sides thereof a metal-bearing plastic coatingv This metallized plastic coating acts as a reflective barrier to heat transmitted by radiation dur- 9 Claims, 3 Drawing Figures PATENTEDmmIw 3.6862800 FIG. 1 FIG..2

FIG. 3

INVENTORS CHARLES l RUE- JOHN F. EUSCH ATTORNEY ABRASIVE CUTTING-OFF WHEELS HAVING METAL COATED SIDES This invention relates to new and improved cuttingoff wheels. More particularly, it relates to resinoid bonded abrasive cutting-off wheels having metal coated sides and to methods for the production thereof.

Resinoid bonded cutting-off wheels have been produced for many years and are well known for their use in cutting materials such as metal bars, castings, pipes, structural steel and the like. However, in manufacturing such wheels, it has been a continuing problem to provide wheels which are more heat-resistant. Another problem is the provision of wheels which are more efficient in terms of area of metal cut per unit of wheel wear and in which the wheels wear in a more uniformly flat manner. Yet another problem is to provide wheels which cut more freely and produce less burn on the cut surface.

In an attempt to solve these problems, it has been suggested heretofore to apply metal-foil, such as aluminum foil, to the sides of cutting-off wheels. Also it has been suggested, in [1.8. Pat. No. 2,729,039 issued to H. N. Stone, to secure paper coated with a metal to the sides of a cutting off wheel. The metals suggested therein were tin, antimony, bismuth, cadmium, gallium, indium, lead, thallium and alloys thereof and were chosen because of their low melting points to provide lubrication and anti-sticking during the cutting-off period.

However, the above described problems have not been solved, heretofore. The previously proposed metal coated wheels have been found to be inadequate for a variety of reasons. For example, the necessary thickness of the previous coatings defeated the purpose for which they were intended. This is particularly true of the metal foil coated wheels, since it has been found that the thick foil tends to produce a wheel surface that cannot cut on its side, thus resulting in rubbingand generation of excess heat during the cutting operation. Additionally, it has been discovered that the previously suggested metal coated wheels do not possess adequate heat resistance. As an example, cutting-off wheels of the type described in the Stone patent are coated with metals having low melting points, thus rather than acting as a heat shield for the wheel surface, the metals melt and provide a certain degree of lubrication but do not provide heat resistance.

A further detrimental feature of prior art metal coated cutting-off wheels is that the coating has a tendency to peel off or scrape off during the cutting process. This is an inherent problem with the heretofore known cutting-off wheels such as those having a metal coating on a paper surface, as described by Stone, and those employing a metal foil coating. This tends to cause the wheel to bind during cutting and cause burning of the cut surface.

It is therefore, an object of the present invention to provide resinoid bonded abrasive cutting-off wheels having greater heat-resistant characteristics.

Another object is to provide metal coated cutting-off wheels in which the coating is very thin and adheres very effectively to the surface of the wheel and has n tendency to peel off or scrape off.

Another object is to provide more efficient cuttingoff wheels in terms of area of metal cut per unit area of wheel wear.

Another object is to provide cutting-off wheels in which the face of the wheel wears in a more uniformly flat manner.

A further object is to provide cutting-off wheels which cut more freely and produce less burn on the cut surface.

A still further object is to provide more economical methods for producing resinoid bonded abrasive cutting-off wheels having metal coated sides, these cutting-off wheels exhibiting improved heat resistance characteristics and being more efficient and effective in operation.

An additional object is to provide a more economical resinoid bonded abrasive cutting-off wheel.

Other objects, if not specifically set forth herein, will be readily apparent to those skilled in the art from the following detailed description of the invention.

According to one aspect of the invention, a cuttingoff wheel is constructed having an abrasive matrix including a plurality of abrasive grains and a resinous bonding agent. The cutting-off wheel is coated on both sides with a very thin metallized film layer. This metallized film covering acts as a reflective barrier to heat transmitted by radiation during the cutting process. Thus, the inventive cutting-off wheels are more heat resistant than wheels known heretofore.

The above mentioned and other features and objects of this invention and the manner of obtaining them will become more apparent, and the invention itself will be best understood by reference to the following description of embodiments of the invention taken in conjunction with the corresponding drawings, in which:

FIG. 1 is a front perspective view of a cutting-off wheel of the present'invention;

FIG. 2 is a cross-sectional view of the cutting-off wheel taken along line l-l of FIG. 1; and

FIG. 3 is a perspective view of a preferred embodiment of a cutting-off wheel according to the present invention, showing the cutting-off wheel mounted in position during a typical cutting operation.

Briefly, a resinoid bonded abrasive cutting-off wheel 10 is shown in FIG. 1 and FIG. 2 to illustrate a preferred embodiment exemplifying the principles of the invention. In general, this embodiment includes a circular shaped cutting wheel body, generally indicated as 10, having an abrasive matrix 12 including a plurality of abrasive grains and a resinous bonding agent. The cutting-off wheel 10 has, applied to both sides thereof, very thin sheets of metal-bearing plastic 14 which act as reflective barriers to heat transmitted by radiation during cutting operations. The metal-bearing plastic sheets 14 are applied, in the form of thin films, in a uniform manner to the entire surface of both sides of the cutting-off wheel 10 from a position adjacent to the periphery of the wheel to a position adjacent to the hub or center hole 16 of the wheel 10.

In greater detail, the resinoid bonded abrasive cutting-off wheel 10 is constructed of abrasive grains bonded with a thermosetting resin. Affixed to both sides of the wheel 10 is a metal-bearing plastic 14 which adheres extremely effectively to the abrasive surface and has no tendency to peel off or to'scrape off during the cutting operation of the wheel. The metalbearing plastic 14 preferably comprises an extremely thin metallized polyester film coated with a reflective metal. However, it is also within the scope of this invention to employ plastic films and the like in which the metal is included in the plastic itself as opposed to being coated or deposited on the surface thereof.

Examples of suitable reflective metals for use in the present invention include aluminum, nickel, chromium, copper, gold, platinum, silver and the like and mixtures thereof. From the standpoint of cost and ease of application, the preferred metal to be used is aluminum.

The thickness of the metal-bearing plastic sheets 14 to be employed herein is variable within limits determined by practical cutting effectiveness. However, it is preferred that the thickness of the metal layer coated on these plastic sheets 14 not exceed about 0.0002 inch. In a most preferred embodiment, the thickness of the metal layer should be less than about 0.00002 inch.

From the foregoing, the operation of the inventive cutting-off wheel should be apparent to those skilled in the art. In greater detail and with reference to FIG. 3, the cutting-off wheel is operatively attached to a drive means (not shown) by a horizontally extending bearing means 18 of the drive means. The bearing means 18 which attaches the wheel 10 to the drive means and also supports the wheel 10 is fixably attached to hub 16 of wheel 10 by a standard flat mounting flange 20 and nut 22. Thus, the rotation of bearing means 18, indicated in FIG. 3 by arrow (a), imparted by the drive means, causes the wheel 10 to rotate in a corresponding manner. Table 24 having a slot 26 is positioned so that a workpiece 28 can be brought into contact with the cutting surface 29 of wheel 10 by moving the wheel 10 in the general direction indicated by arrow (b). It is to be noted that as the cutting action of wheel 10 is progressing, it is possible for the wheel 10 to oscillate or wobble back and forth slightly in the general direction indicated by arrow c-c.

During the cutting operation, the heat generated can cause a drastic reduction in useful life of the wheel as a result of excessive wear. It has, therefore, been a long standing problem to produce more heat resistant wheels. However, the heretofore proposed wheels having coatings on the sides thereof which were meant to increase heat resistance have not been successful. For example, the above mentioned oscillation or wobble, inherent in the operation of cutting-off wheels, can cause the wheel to rub or bind and burn the cutting surface. In the case of the heretofore proposed coated wheels, this action would cause the coating material to detach from the surface of the wheel and cause even more possible burning of the cut surface in addition to defeating a purpose for which the coating was intended (i.e., to protect the wheel from heat wear).

In the present invention, as the cutting action progresses, there is no tendency for the metal-bearing plastic coating 14 to peel or scrape off as a result of the oscillating or wobbling action. Thus, the wheel is very effectively protected from heat wear. Further, the wheel cuts freer and faster and produces much less burn as compared, for example, with metal-foil coated wheels.

The following example is set forth for the purpose of illustrating the method of producing the inventive cutting-off wheels and to demonstrate the superiority in operation thereof over heretofore proposed cutting-off wheels. However, this example is not intended to be construed as being limitative in any respect.

EXAMPLE I Two sets of wheels were constructed having 16 inch diameters, 0.165 inch thickness and 1% inch center holes.

One set of seven wheels (hereinafter referred to as set A) was produced as a control to illustrate the heretofore available coated cutting-off wheels. Each of the seven wheels of set A had 0.001 inch aluminum foil covering on each side thereof.

The second set of wheels (hereinafterreferred to as set E) was produced according to the present invention. Each of the seven wheels of set B had'coated on both sides thereof a 0.0005 inch Mylar polyester film (a product of El. DuPont De Nemours Co.,Inc. of Wilmington, Delaware). Each of the Mylar films was coated with a layer of aluminum about 0.000005 inch thick.

The formula of the mix used to produce both of the sets of cutting-off wheels (set A and set B) was as follows:

24 grit fused aluminum oxide 66.25% by weight liquid phenolic resin 3.83

powdered phenolic resin 8.93 powdered iron pyrites 18.48 calcium oxide 251 Total 100.00

under a pressure of 2 tons per square inch between platens heated to 350 F. Pressure and temperature were maintained for 10 minutes. The resulting wheels were placed on batts and cured in an oven for 20 hours, the final 14 hours being at 350 F.

The coatings were applied to the wheels of set B by a corresponding procedure. That is, a thin layer of aluminized polyester film was placed in the bottom of a 16 inch mold, then 1,468 grams of mix was added and leveled. A second thin aluminized polyester film was added and a top plate inserted and the mold was pressed under a pressure of 2 tons per square inch between platens heated to 350 F. Pressure and temperature were maintained for 10 minutes. The resulting wheels were placed on batts and cured in an oven for 20 hours, the final 14 hours being at 350 F.

Both sets of wheels when finished were subjected to testing on a Wallace 15 hp. cut-off machine, cutting off 2X2 cold rolled steel bars. The results of this testing are tabulated in the following table:

Seconds/Cut Steel-to-Wheel Wheel (average Ratio No. of 10 cuts) Burn (in /in) 1 15 81 3.25 2 12 85 3.25 SET A 3 ll 61 2.89 4 15 89 2.61 5 14 77 2.89 6 14 82 2.38 7 9 27 2.52 Ave. 12.9 71.7 2.83 1 13 52 5.16 2 12 62 4.31

SET B 3 9 0 3.25 4 22 3.45 5 12 58 4.26 6 9 0 3.66 7 8 o 3.66 Ave 10.4 27.7 3.96

"Steel to Wheel ratio is square inches of metal inches of wheel consumed.

cut divided by square It is to be noted from the results of this testing that cutting-off wheels of the present invention with aluminized polyester coated sides are much more efficient than those sided with aluminum foil. The inventive wheels cut freer and faster and produce much less burn than the aluminum foil-sided wheels.

While the principles of the invention have been described above in connection with specific apparatus and applications, it is to be understood that this description is made only by way of example and not as a limitation on the scope of the invention.

We claim: t

1. An abrasive cutting-off wheel comprising a circular wheel body having affixed to both sides thereof a heat-resistant metal-bearing plastic coating. 7

2. The abrasive cutting-off wheel of claim 1 wherein said metal-bearing plastic coating comprises a thin metallized polyester film.

3. The abrasive cutting-off wheel of claim 1 wherein 7 6 the metal included in said metal-bearing plastic coating comprises a reflective metal.

4. The abrasive cutting-off wheel of claim 3 wherein said reflective metal is selected from the group consisting of aluminum, nickel, chromium, copper, gold, platinum, silver and mixtures thereof.

5. The abrasive cutting-off wheel of claim 1 wherein said metal-bearing plastic coating comprises a plastic sheet coated with a layer of reflective metal.

6. The abrasive cutting-off wheel of claim 5 wherein said layer of reflective metal has a thickness of less than about 0.0002 inch.

7. An abrasive cutting-off wheel comprising a circular wheel body having aflixed to both sides thereof a metallized polyester film coating, said metallized film coating including a layer of reflective metal coated on the surface of said film, and the thickness of said metal layer being less than about 0.0002 inch.

8. The abrasive cutting-off wheel of claim 7 wherein the thickness of said metal layer is less than about 0.00002 inch.

9. The abrasive cutting-off wheel of claim 7 wherein said reflective metal is selected from the group consisting of aluminum, nickel, chromium, copper, gold,

platinum, silver and mixtures thereof. 

2. The abrasive cutting-off wheel of claim 1 wherein said metal-bearing plastic coating comprises a thin metallized polyester film.
 3. The abrasive cutting-off wheel of claim 1 wherein the metal included in said metal-bearing plastic coating comprises a reflective metal.
 4. The abrasive cutting-off wheel of claim 3 wherein said reflective metal is selected from the group consisting of aluminum, nickel, chromium, copper, gold, platinum, silver and mixtures thereof.
 5. The abrasive cutting-off wheel of claim 1 wherein said metal-bearing plastic coating comprises a plastic sheet coated with a layer of reflective metal.
 6. The abrasive cutting-off wheel of claim 5 wherein said layer of reflective metal has a thickness of less than about 0.0002 inch.
 7. An abrasive cutting-off wheel comprising a circular wheel body having affixed to both sides thereof a metallized polyester film coating, said metallized film coating including a layer of reflective metal coated on the surface of said film, and the thickness of said metal layer being less than about 0.0002 inch.
 8. The abrasive cutting-off wheel of claim 7 wherein the thickness of said metal layer is less than about 0.00002 inch.
 9. The abrasive cutting-off wheel of claim 7 wherein said reflective metal is selected from the group consisting of aluminum, nickel, chromium, copper, gold, platinum, silver and mixtures thereof. 